TBC. Arena was fresh and fun back then, and although there was balance issues of course like always, they didn't seem as hopeless to overcome. Not saying it was the most competetive nor balanced but for me it was the most enjoyable expansion.

The community was on it's prime as well imo, nowadays it's just generic kids competing with eachother who's the most disgusting little shit and using same boring antics (yolo, swag, dog, cy@ etc.) that makes me wanna go get a vasectomy done.

every season where 2s gave glads was better, ladder was so much more active and actually fun even though the typical OPs most of the time took r1, some people made a name for themselves just in the 2s bracket alone(e.g. the infamous #1 dualmage world sai/ayrez in wotlk )

My personal choice is MoP for one simple reason: The need to raid as PvP player is over, no need to farm (or bot, which I never did) constantly. Means I have time to play two classes and simply have fun doing so. I don't even mind the upgrades, it makes the ladders relatively active. 5.2 has issues, especially for mages and druids and looks to have overbuffed classes (not too unhappy, as I play Mistweaver Monk and Rogue).

Aside from the usual balance issues the tournament so far showed that 10/11 classes can compete on high levels. Balance issues will remain within WoW and within any game with character development. It creates however the opportunity for underdogs to win despite the odds.

I say BC as number 1 because the game was just so much more alive and thriving, it was possible to have fun doing BG's, heroics, etc. Everything wasn't a checklist on how to get gear for 70, there were many options on what you could do at max level to gear up and still do arenas, or raids.

Wrath two just because it was entertaining (discounting season 5) the high damage was incredibly broken but fun.

MoP is similar to wrath to me except the game is just dead as all hell, playstyle feels similar.

Cata biggest pile of dog shit I've ever seen, unless you were a warlock rogue or shaman and I'm not saying that offensively it's just how it felt for me, I played a UA lock myself.

tbc, then wrath. imo you can't even compare the other expansions, tbc and wrath were so much better in all aspects of the game. i know vanilla isn't an expansion, but that was a fantastic game in terms of pve, pvp was ok back then, 2 shotting mages and locks never got old

The reason why i choose MOP is because as the OP said, its my first competive season and maybe the season i will get my first gladiator title if everything goes well. I never really focused on PvP other then this season and for a few month last season untill i quitted.